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Relationship between Cervical Mucus Interleukin-8 Concentrations and Vaginal Bacteria in Pregnancy


Address reprint requests to Shigeru Saito, Professor and Chairman, Department of Obstetrics and Gynecology, Toyama Medical and Pharmaceutical University, Toyama-Sugitani 2630, Toyama 930-0194, Japan.


Problem:  High interleukin (IL)-8 concentration in cervical mucus in the second trimester is a risk factor for premature birth. We investigated the relationship between vaginal pathogens and IL-8 in cervical mucus.

Method of study:  In 501 women with single pregnancy, vaginal secretions were cultured for bacteria and cervical mucus IL-8 concentrations were measured between 20 and 24 gestational weeks.

Results: Lactobacillus species were detected in 56.0% of 84 subjects with high IL-8 (≥377 ng/mL), significantly less often than in 417 subjects with IL-8 below 377 ng/mL (84.7%; P < 0.0001). Anaerobic pathogens were detected in 83.3% of high IL-8 subjects, significantly more often than in normal IL-8 subjects (43.9%; P < 0.0001). By multivariate analysis, cervical IL-8 was significantly high only in subjects without Lactobacillus species; they showed a significantly higher prematurity rate than Lactobacillus-positive subjects.

Conclusions:  Absence of vaginal Lactobacilli was associated with increased cervical IL-8 and increased risk of premature delivery.